<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <meta http-equiv="X-UA-Compatible" content="ie=edge">
        <title>Document</title>
        <style>
        
        *{

            margin: 0px;
            padding: 0px;
            list-style:none;

        }
        div{

            width: 600px;
            height: 398px;
            margin: 100px auto;
            position: relative;
            overflow: hidden;

        }
        ul{
            width: 9999px;
        }
        ul li{
            float: left;
        }
        ol{
            position: absolute;
            bottom: 20px;
            left: 50%;
            transform: translateX(-50%);
        }
        ol li{
            width: 8px;
            height: 8px;
            background: rgb(228, 41, 166);
            border-radius: 50%;
            margin: 0px 4px;
            float: left;
            cursor: pointer;

        }
        span{
            position: absolute;
            /*background: salmon;*/
            top: 50%;
            transform: translateY(-50%);
            cursor: pointer;
            color: rgb(220, 59, 153);

        }
        span:nth-of-type(1){
            left: 10px;

        }
        span:nth-of-type(2){
            right: 10px;
            
        }
        .current{
            background: rgb(162, 68, 134);
        }
        </style>
    </head>
    <body>
        <div id="wrap">
                <ul id="box">
                    <li>
                    <img src="pic1.jpg" alt="">
                    </li>
               
                    <li>
                    <img src="pic2.jpg" alt="">
                    </li>
               
                    <li>
                    <img src="pic3.jpg" alt="">
                    </li>
               
                    <li>
                    <img src="pic4.jpg" alt="">
                    </li>
                </ul>

                <ol id="list">
                    <li class="current"></li>
                    <li></li>
                    <li></li>
                    <li></li>
                </ol>
                
                <span id="left">L</span>
                <span id="right">R</span>
        </div>
            <script>
                var box=document.getElementById('box');
                var wrap=document.getElementById('wrap');
                var list=document.getElementById('list').children;
                var left=document.getElementById('left');
                var right=document.getElementById('right');

                var num=0;
                var timer;


                
                function fn(){
                timer=setInterval(function(){
                    num++;
                    if(num>3){
                        num=0;
                    }
                    var t=-num*600;
                    box.style.transform='translateX('+t+'px)';

                    for(var j=0;j<list.length;j++){
                        list[j].className='';
                    }
                    list[num].className='current'
                },1000)
                }

                wrap.onmouseenter=function(){

                    clearInterval(timer)
                }
                wrap.onmouseleave=function(){
                    /* timer=setInterval(function(){
                    num++;
                    if(num>3){
                        num=0;
                    }
                    var t=-num*520;
                    box.style.transform='translateX('+t+'px)'
                },1000)*/
                fn()
                }


                for(var i=0;i<list.length;i++){

                    list[i].index=i;
                    list[i].onclick=function(){

                        for(var j=0;j<list.length;j++){
                            list[j].className='';

                        }
                        this.className='current';
                        num=this.index;
                        var t=-num*600;
                        box.style.transform='translateX('+t+'px)';
                    }
                }
                right.onclick=function(){
                    num++;
                    if(num>3){
                        num=0;
                    }
                    var t=-num*600;
                    box.style.transform='translateX('+t+'px)';

                    for(var j=0;j<list.length;j++){
                        list[j].className='';
                    }
                    list[num].className='current'
                }
                left.onclick=function(){
                    num--;
                    if(num<0){
                        num=3;
                    }
                    var t=-num*600;
                    box.style.transform='translateX('+t+'px)';

                    for(var j=0;j<list.length;j++){
                        list[j].className='';
                    }
                    list[num].className='current'
                }


                
            </script>
    </body>
</html>